Controlling means and actuating means therefor



Nov. 24, 1942. E 1 DlLLMAN 2,303,028

CONTROLLING MEANS AND ACTUATING MEANS THEREFOR @wd/uf J1. M

la; ATTORNEY NOV- 24, 1942- v E. J. DILLMAN 2,303,028

CONTROLLING MEANS AND ACTUATING MEANS THEREFOR Filed July 3, 1941 5 Sheets-Sheet Nov. 24, 1942. E 1 D|| L MAN 303,028

CONTROLLING MEANS AND ACTUATING MEANS THEHEFOR Filed July 3, 1941 5 Sheets-Sheet 3 Patented Nov. 24, 1942 CONTROLLING MEANS AND ACTUATING MEANS THEREFOR Earnest J. Dillman, Detroit, Mich., assigner to Detroit Lubricator Company, Detroit, Mich., a.

corporation of Michigan Application July 3, 1941, Serial No. 400,939

(Cl. 20G-138) 27 Claims.

This invention relates generally to n-ew and useful improvements in controlling means and actuating means therefor and which among other uses is particularly adapted for use to operate switches such as the fan and limit switches employed in heating systems.

One object of this invention is to provide a novel means for actuating a controlling means.

Another object is to provide a readily accessible means for adjusting the actuating means.

Another object is to provide a structure in whichthe controlling means is easily removable as an independent unit.

Another object is to provide the actuating means with a means for indicating the operation of the actuating means.

Another object is to provide an actuating means in which the controlling means is held in its actuated position subsequent to its actuation.

Another object is to provide means for overtravel of the actuating means.

Another object is to provide in a fan and limit control, means for interrelating the fan adjustment to the limit adjustment to insure closure of the fan switch prior tc opening of the limit switch.

Another object is to provide means for limiting the maximum temperature at which the actuating means may be set by the operator for opening of the limit switch.

Another object is to provide a novel snap acting switch means.

Other objects Will be apparent from a reading p of the specication and the appended claims.

The invention consists of the improved construction of and combination of parts to be more fully described hereinafter and the novelty'of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings, to be taken as a part of this specication, there is fully and clearly illustrated a preferred embodiment of the invention in which drawings:

Figure l is a view in side elevation with the cover removed of a fan and limit switch mechanism embodying invention;

Fig. 2 is a View in front elevation with the cover removed of the mechanism of Fig. l;

Fig. 3 is a view taken substantially along the line 3-3 of Fig. l;

Fig. 4 is a vi-ew taken substantially along the line 4-4 of Fig. 2;

Fig. 5 is an exploded View of certain of the parts of the switch actuating mechanism;

Fig. 6 is a top plan view of the switch unit with the cover removed;

Fig. 7 is a view taken substantially along the line 'l-`l of Fig. 6;

Fig. 8 is a view taken substantially along the line 8-8 of Fig. 6, and

Fig. 9 is a top plan view of the actuating cam for the switch unit.

Referring to the drawings by characters of reference, the numeral I designates generally a fan and limit switch mechanism having a housing 2, a hollow tubular supporting member 3 and a helical bimetallic actuating element 4. A mounting l ange 4 which is securely fastened to the wall Isertion of the member 3 into the ange 4. The

housing 2 is preferably U-shaped and has a rear wall 5, a top wall 6 and a bottom wall 'I. -A U- shaped cover member 8 having a front wall 9 and end walls I0 and I I cooperates with the housing 2 to form a completely enclosed hollow casing for the switch units and the switch actuating mechanism to be described hereinafter. A bracket member I2 is secured at its opposite end portions to the extending or front edge portions of the walls 6 and l as by screws I3 and acts to hold the walls '6 and l in relative xed space relation. A stub screw I4 is secured, as by riveting, to the member I2 and is positioned substantially midway between the walls 6 and 'I and extends through an aperture in the cover member front wall 9. A cap nut I5 rotatably secured to the wall 9 has screw-threaded connection with the screw I4 for holding the cover member 8 in its cooperative relation with the housing 2. One end of the bimetallic element 4 is secured as by means of a screw to a tab I6 which extends longitudinally outward from the supporting member 3 and the other end of the element is secured as by means of a screw to a attened end portion Il of a rod I8 which extends longitudinally of and beyond the end portion of the supporting member 3 having the tab IB. The tab I'6 has an inturned portion I8 extending through the 1ongitudinal center line or axis of the member 3 and has an aperture therethrough in which the rod I8 is journaled. The other end portion of the member 3 -is rigidly secured to the rear wall 5.. of the housing 2 as by means of four equally spaced tabs |9 which are peened to the wall 5.

-The rod |8 extends through an aperture 28 in ture therethrough aligned with the aperture 28,

through the rear wall 5, in which is secured a bearing member 22. The rod I8 extends through and is journaled for rotational movement in the member 22. The bracket 2| has adjacent the wall 6 a pair of offset lip portions forming slide rails 23, 24 spaced substantially parallel to the plane of the bracket 2| and positioned on the bracket 2| front surface 9, the rails being positioned on each side of the bearing member 22 and substantially equidistant therefrom and the outer edge surfaces of the bracket 2|. 'A pair of offset lip portions forming slide rails 26, 21 are carried by the bracket 2| adjacent the wall 1 and are disposed in facing relationship to the rails 23 and 24 and in a similar position with respect to the bearing member 22. A first switch unit generally designated 28 and having a bottom casing portion 29 and a casing cover 38 is positioned against the front surface 25 and wedge shaped ears 3| extending outward from the opposite end walls or surfaces 3|, 3|b of the casing portion 29 are positioned intermediate the rails 23 and 26 and cooperate therewith to hold the switch unit against the surface 25. When the cover member.8 is removed, the switch unit 28 may be slid through the open end wall I8 along the surface 25 until a recess in. an edge portion 32 of the unit 28 perpendicular to the end surfaces 3|Il and 3|h engages the bearing member 22 as a stop. The edge portion of the bracket 2| adjacent the wall has a downturned lip portion 33 extending toward the wall in which is threaded a screw 34 having a large head thatA engages an edge portion 35 of the unit 28 opposite to the portion 32 to hold the unit 28 against the member 22 and the ears within the rails 23 and 26.

A second switch unit 36 similar to the unit 28 has a bottom casing portion 31, a casing cover 38, wedge shaped ears 39, an edge portion 48 engageable with the bearing member 22, and an edge portion 4| engaged by a screw 42 having a large head and screw threaded to a downturned lip portion 43 of the bracket 2| extending toward the wall 5 adjacent the wall Referring to Figs. 6-9, wherein the switch unit 28 is shown in detail, the bottom casing portion 29 carries a U-shaped bracket 58 adjacent the end wall 3| and held to the top surface of the portion 29 as by screws 52. Knife edge slots 53 in the facing surfaces of the parallel portions of the bracket 58 receive the end portions of a reacting means 54 such as a leaf spring. The free length of the spring 54 is greater than the distance between the slots 53 so that the spring 54 is held in a bowed position. The spring 54 may be flexed to either of its bowed positions by a bell crank lever 55 which has a straight platelike rectangular lever arm or member 56 which may be made of Bakelite or other insulating material and an L-shaped metallic member 51. The member 51 is of the same width as the spring 54 and one arm thereof which extends parallel which faces the wall with a portion of the spring 54, has oppositely extending lips or ears which are rebent about the spring 54 adjacent one end portion thereof to secure the lever to one face of the spring 54. A rivet 58 secures one end of the member 56 to the other arm of the member 51 so that as the extending end of the member 56 is moved laterally relative to the switch unit 28 and'longitudinally of the spring 5'4, the spring 54 is flexed through center from one bowed position to another bowed position. As the lever member or arm 56 is moved toward the left, facing Fig. 8, it `fulcrums on the spring 54 tending to stress the spring into an S-curve which raises the midportion of the spring 54 toward and ultimately through center, i. e. the straight line joining the spring ends. The casing bottom portion 29 and cover 38 have protruding abutments 58HL which are positioned adjacent the end portions of the spring 54 and on both sides thereof so that should the lever 55 be excessively moved, the end portions of the spring 54 will not jump out of the slots 53. During normal operation of the spring 54, the abutments 58- have no function. A switch 58b comprises a current conducting switch blade 59 which haslone end secured to the casing portion 29 adjacent the end wall or surface 3|h and the wall 35, and extends longitudinally of the portion 29 and also is offset toward the wall 32. The blade 59 has at its other end portion an end slot which receives the transversely extending spring 54 at a point substantially two-thirds of the distance between the connection of the lever 55 to the spring 54 and the other end portion of the spring 54. A contact member 68 is carried by the blade 59 adjacent the slot and cooperates with a fixed contact member 6| carried by a current ,conducting member 62 which is held rigid with the casing 29 and extends substantially transverse to the blade 59. Upon movement of the bell crank lever 55 in a counterclockwise direction (see Fig. 8), the spring 54 will be moved to its bowed upward position and the blade 59 will be moved upward with a snap action thereby causing the contact members 68 and 6| to engage to complete an electric circuit. As the bell crank lever 55 is moved clockwise, the spring 54 will be moved to its bowed downward position and the blade 59 will be moved downward with a snap action thereby to part the contact members 68 and 6| and open the electric circuit. The transverse member 62 has a portion 63 which extends externally of the casing portion 29 and carries a connecting screw 63EL for conveniently connecting one lead wire of the circuit to be controlled to the fixed contact member 62. A T-shaped member 64 has a portion 64a extending externally of the casing portion 29 which has a connecting screw 64b for conveniently connecting the other lead wire of the circuit to be controlled. One of the oppositely extending portions of the T-shaped member 64 underlies and is in electrical contact with the secured end of the blade 59 so that the lead wire which is connected to the screw 64b is electrically connected to the movable upwardly facing contact member 68. The casing cover 38 conforms in external contour to the casing bottom portion 29 and has a recessed portion which receives and encloses the parts carried by the bottom portion 29 to protect them from accidental contact with foreign substances. The bottom portion 29 has a supporting' post 65 which extends upward and through an aperture in the cover 30. A stub shaft 66 is carried by the post 85 and extends upward therefrom to form a pivotal support for a U-shaped cam member 61, to be described more in detail hereinafter. The second switch unit 36 is constructed similarly to switch unit 28 and has a bell crank lever 68, a switch (not shown), terminal screws 10, 1| for connection to an electric circuit, a stub shaft 12, and a U-shaped cam member 13.

Fig. 5 shows the adjustable mechanism for actuating the cam members 61 and 13. The numeral 14 designates a cylindrical post or sleeve member having an outwardly extending peripheral flange at its lower end portion and having flattened diametricaliy opposed wall portions 16. A helical coil spring 11surrounds the sleeve member 14 and has one end portion seating against the flange 15 and has its other end portion abutting a washer or annular plate member 18 which is positioned on and concentric with the member 14. The inner periphery of the member 18 is circular and of substantially the same diameter as the member 14. A second annular plate member 19 is positioned on and concentric with the'member 14 and has one surface in contact with the annular member 18. The inner contour of the member 19 is not a true circle but has chord-like portions which conform to the flattened portions 16 so that the second member 19 is held against rotational movement relative to the member 14. A third annular member 8| having an upwardly offset annular central portion 82 and having a fan shaped segment 83 extending outward from and offset upwardly from its periphery, is positioned Aon and concentric with'the cylindrical member 14, with the outer portion of the member 8| against the upper surface of the second member 19. The contour of the inner periphery of the member 8| is circular so that it may be rotated relative to the member'14. A fourth annular member 84 has anoffset downwardly annular central portion 85 which engages the upwardly offset portion 82 and has a fan shaped segment 86, similar in size and shape to the segment 83, offset upwardly from its periphery so that it overlies the segment 83. A fifth annular member 81, identical With the second annular member 19, has its lower surface in contact with the outer portion ofthe member 84 and has chord-like portions 88 conforming to the flattened portions 16 so that the fifth member 81 is held against rotational movement relative to the member 14. A sixth annular member 89 similar to the third ai-jd fourth members 8| and 84 has an offset upwardly annular central portion 90 and an offset downwardly fan-like segment 9| at its periphery. 'I'he contour of the inner periphery of the member 89 like that of the members 8| and 84 is circular so that the member 89 may be rotated relative to the cylindrical member 14. The outer portion of the member 89 engages the upper surface of the fifth member 81. A seventh annular member 92 has an offset downwardly central annular portion 93 which engages the offset unwardly portion 90 and has an offset downwardly fan-like segment 94 which overlies the segment 9|. The contour of the inner periphery of the member 92 is circular so that the member 92 may be rotated relative to the cylindrical member 14. The member 92 has at its outer periphery a downturned lug or ear 94a which is engageable with an edge portion of the segments 83 and/or 86 to limit relative movement between the segments 83, 86 and 9|, 94. An eighth annular member 95 identical with the second and fifth annular members 19 and 81 has its lower surface engaging the outer portion of the member 92 and has chord-like portions 96 conforming to the flattened portions 16 so that the eighth member 95 is held against rotational movement relative to the member 14. The cylindrical member 14 has a central aperture 91 extending longitudinally therethrough and of a reduced diameter relative to the normal diameter of the rod |8.4 `At the upper end portion of the member 14 opposite tothe flange 15, there is an annular protuberance 98 which is concentric with the aperture 91 and is received within a central aperture 98 of a disk member 99 so that the lowerV surface of the member 99 can seat against the upper end surface of the cylindrical member 14. The disk member 99 is held in position as by the peening of the annular protuberance 98 and acts upon engagement of its lower surface with the upper surface of the eighth member 95 to hold the member 95 against movement in an upward direction. The force exerted by the spring 11 acts to frictionally hold all of the eight annular members '18, 19, 8J, 84, 81, 89, 92 and 95 in tight frictional engagement so that rotation of the cylindrical member 14 will cause a corresponding rotation of the annular members 8| and 84, and 89 and 92 which are manually rotatable relative to the cylindrical member 14 for adjustment thereof. The adjustable mechanism generally designated |00 for convenience, comprises all of the elements designated by the numerals 14-99 each inclusive.

The end portion of the rod I8 which is positioned intermediate the bearing member 22 and thebracket member I2, is of reduced diameter for insertion into the aperture 91 of the mechanism |00. SubsequentI to assembly, the mechanism |00 is secured rigid to the rod I8 as by solder which is received in a space |0011L formed between the inner periphery of the annular protuberance 98 and the reduced diameter portion of the rod I8. The segment 83 has a downwardly protruding abutment |0| which comprises a stubshaft bearing |02 secured to the segment 83 as by riveting and having a tubular roller portion |03 rotatable about the bearing 02 and held thereon by a head portion |04. The segment 86 has a protruding abutment |05 similar to the abutment |0| comprising a stub shaft bearing |06, and a tubular roller portion |01 held on the bearing |06 by a head portion |08. The abutment |05 extends through an arcuate slot |09 in the segment 83 and the segment 86 has an arcuate slot |09 receiving the riveted end of thev stub shaft bearing |02 so that it does not interfere with manual relative movement of the members 8| and 84. The segments 9| and 94 are similarly arranged to the segments 83 and 86 with arcuate slots ||0 and respectively, the abutments ||2 and ||3 respectively, have roller portions H4, ||5 and stub bearings ||6, ||1. The segments 83, 86, 9| and 94 have upstanding tabs ||8, H9, |20 and |2| respectively, which extend beyond the upper surface of the disk member 99 and have respectively inwardly extending radial pointers |22, |23, |24 and |25 which cooperate with an indicia plate |26 adjustably secured as by a screw |21 to the upper surface of the disk member 99 to indicate the temperature at which the switch units 28 and 35 are actuated. The bracket member |2 has a perpendicularly extending finger-or pointer |28 which cooperates with the indicia plate |26 to indicate by a screw |3| and -has a portion |32 which lies in the path of movement of the tab I2I to limit the maximum temperature at which the member 92 may be set to actuate the switch unit 36. An arrow |33 which may be engraved in the front surface of the stop plate |30 cooperates with the indicia plate |26 to indicate the maximum ternperature at which the plate |30 is set.

' The /lgenerally U-shaped cam members 61 and 13 are in the form. of rockable levers, the member 61 being shown in detail in Fig. 9. Projecting fromthe base of lever 61 are spaced and opposed arms or cams |34, |35which diverge outwardly from the base. 'The inner face of cam |34 has a cam surface |36 from which thereextends at an angle but in continuation thereof a curved cam holding surface |31. The inner face of camI |35 which faces or. is opposed to the face of cam |34 has a cam surfaceV |38 substantially parallel to surface |36. Extending from and in continuation of surface |38 but at an angle thereto there is a curved cam holding surface |39. The

lever 61 has an arm or ear |40 projecting longitudinally from its base adjacent the arm |35. Through the ear |40 there is an hour-glass type slot |4| which receives the switch operating arm 56. The members or levers 61 and 13 are mirror copies of each other and therefore the exponent a applied to the reference characters designating the parts of lever 61 will designate like parts of the lever 13. The abutment members or posts |0| and |05, carried respectively by the segments 83 and 86 which form part of the oscillatable operating means for switch unit 28, travel in an arc concentric with shaft I8. The curvature of the holding surfaces |31 and |39 conforms to the arc inscribed by the radially outermost surfaces of the abutment members |0| and |05. The post or fulcrum 66 of lever 61 is positioned mid-way between the cams |34 and |35 and such that when lever 61 is rocked counterclockwise, facing Figs. 3 and 9, the holding surface |39 will be substantially concentric with shaft I8 and lie substantially parallel to the path of travel of abutment members I 0| and |05. The holding surface |31 is eccentric to surface |39 and so positioned that on clockwise rotation of lever 61, it will be movable into a position substantially concentric with shaft I8 and lie substantially parallel to the path of travel of abutment members |0I and |05. The cam sur- Laces |36, |38 are, upon rocking of lever 61, alter- -lately movable into the arc or path of travel of the abutment members |0| and |05 respectively. As the parts are positioned in Fig. 3, clockwise rotation of shaft I8 has just moved abutment member |05 into engagement with cam surface |38. Continued clockwise rotation of the shaft |8 will cause the abutment |05 to cam or rock the lever 61 counterclockwise about the shaft 66 against the force of bowed spring 54. When lever 61 has been rocked sufficiently to snap the spring 54 through center, the lever 61 will have continued movement by the reaction of spring 54 which will position the holding surface I 39 75 substantially in a space position corresponding to the arc described by the abutment members |0| and |05. Further, clockwise rotation of the shaft I8 will cause the abutment member |05, and, if sufficient rotation is had, the abutment member |0I, to move along the holding surface |39 and hold the lever 61 in this position. The segment slot |09 acts to limit relative movement of the members 8| and 84 so that the maximum distance between the abutment members |0| and |05 is always less than the distance between the cam surfaces |36 and |38 as described. Upon counterclockwise rotation of the shaft I8, the abutment members |0| and |05 are rotated toward the cam surface |36 which was positioned in the path of movement of the member |0| when :he lever 61 was moved counterclockwise by the engagement of the abutment member |05 with the cam surface |38 and by the action of spring 54. Continued counterclockwise rotation of the shaft I8 causes the abutment; member |0| t engage surface |36 and rotate the lever 61 about its shaft 66 against the force of spring 54. When the spring 54 has been moved through center, it will react on lever 61 to continue the lever movement to position the holding surface |31 concentric with the arc traced by the abutment members I0| and |05. Further counterclockwise movement of abutment members |0|` and |05 will now carry them along the holding surface |31, thus locking the switch unit 28 in actuated position.

The switch unit 36 is so mounted on the bracket 2| that the cam member 13, pivotally carried by.

the stub shaft 12, is engaged and rotated by the abutment I I3 upon clockwise rotation of the shaft or rod I8 when the pointer |25 passes a position in alignment with the pointer |28. Likewise, upon counterclockwise rotation of the `shaft I8 the abutment I|2 will engage and rotate the cam member 13 when the pointer |24 passes a position aligned with the pointer |28. The indicia on the indicia plate |26 which cooperates with the pointers |22 and |23 is spaced about the plate |26, and the switch unit 28 is positioned on the bracket 2| to hold the stub shaft 66 so that upon clockwise rotation of the shaft I8 the abutment |05 will rotate the cam member 61 when the pointers |23 and |28 indicate the same temperature. Upon counterclockwise rotation of the shaft I8 the abutment 0| likewisewill rntate the cam member 61 when the pointers |22 and |28 indicate the sametemperature. In assembling the switch I it is necessary merely to place the mechanism |00 only approximately un its correct cooperative relation with the shaft |8 before rigidly soldering them together. Later the temperature of the element 4 may be ascertained and the plate |26 rotated relative to the disk member 99 until the pointer |28 indicates the temperature of the element 4 and the screw I 21 tightened. The temperatures indicated by the pointers |22, |23, |24 and |25 will be the temperatures at which the element 4 will actuate the switch units 28 and 36. With this type of calibration, it is unnecessary to disturb the relatively rigid connections through which the force necessary to actuate the switch is transmitted from the element 4. There being no force transmitted through the plate |26 during normal operation of the switch I, the screw |21 need only be sufficiently tight to prevent any vibrational or gravitational force from causing the plate |26 to slip relative to the disk member 99 of the mechanism |00. Should the switch I lose its calibration for some reason, it is necessary merely to place a thermometer adjacent the element 4, and then loosen the screw |21 and rotate the indicia plate |26 until the pointer |28 indicates the same temperature as is indicated by the thermometer. The pointers |22, |23, |24 and |25 will then require readjustment to the correct readings on the indicia plate |26 at which it is desired to havev the switch units 28 and 36 actuated.

`The bracket member I2 has spaced inturned ears |42 and |43 which are engaged by a radially extending lug |44 integral with the indicia plate 261to prevent or limit undue rotation of the shaft |8` upon anabnormal temperature of the element 4. The lug |44 engages the ear |42 upon a decrease of temperature of the element 4 to about 25 F, and engages the ear |43 at a tempera- ,ture of about 425 F. which temperatures are normally never reached by the element 4. The ears |42 and. |43 are so positioned that at least one of the abutments I I, |05 is always in correct cooperative position with the lever or cam member 61 and that at least one of the abutments I I 2, I3 is always in correct cooperative position with the cam member 13.

The operation of the mechanism is as follows: The parts as shown in the drawings are in l" position such that the switch 58b is in open circuit position and the switch (not shown) positioned within the unit 36 is in closed circuit position. As the temperature of the bemetallic element 4 increases, the rod I8 will be rotated clockwise (see Fig. 3) by the element 4 and the abutment carried by the oscillatable operating means will engage the cam surface portion |38 and will rotate the cam member 61 counterclockwise about the stub shaft 66 thereby moving the bell crank member 55 to bow the spring 54 from the downwardly bowed position shown in Fig. 8 to an upwardly'bowed position. This movement causes the switch 58b to close the circuit controlled thereby andthe holding surface |39 to align itself with the arc of -movement of the abutments |0| and |05. With the 93 F. setting of the annular member 84 as shown by the pointer |23, the switch 58b will be closed when the temperature of the element 4 is about 93 F.' Any further heating of the element 4 will cause the abutment |05 and/or abutment I 0| to ride along the lolding surface |39 without altering the position of the' cam member 61 and/or the operation of the switch 58h. ezAs the temperature of the element 4 increases to about 130 F., the abutment I2 also carried by the oscillatable operating means will engage the cam surface, |36i and will rotate the cam member 13 counterclockwise about the stub shaft 12 causing the bell crank lever 68 to bow the leaf spring (not shown) within the unit 36 causing the contact members therein (not shown) to open the circuit between the screws 16 and 1|. Continued temperature increase of the element 4 Will cause the abutment I |2 and/or abutment I3 to move along the holding surface |31, which like the holding surface |31, will their coincide with the arc traced by the outside of the abutments |I2 and I|3 as the shaft |8 is rotated.

As the temperature of the element 4 decreases to about 120 F., the abutment ||3 will engage the cam surface |38a rotating the cam member 13 clockwise about the stub shaft 12 into the position shown in Fig. 3 to move the bell crank lever 68 thereby bowing the spring (not shown) within the unit 36 and closing the circuit between the screws 10 and 1|. A decrease in temperature below 120 F., causes the abutment I|3 and/or abutment I I2 to move along the cam surface portion |39a without change in the operation of the unit 36. Upon a decrease in temperature of the element 4 to about 68 F., the abutment |0| will engage the cam surface |36 and rotate the cam member 61 clockwise about the stub shaft 66. This clockwise'rotation of member 61 will move the bell crank lever 56 thereby bowing thespring 54 into the position shown in Fig. 8 and causing the switch 58h to open the circuit between the screws 63EL and 64b. Should the temperature of the element 4 decrease below 68 F., the abutment I 0| and/or abutment |05 will move along the holding surface |31 without change in operation of the switch unit 28.'

The annular temperature setting members 8|,y

the edge portion' of the segment 83 and/or segment 86 to prevent the members 8| and 84 from being adjusted so that the switch 581 is closed or opened less than 25 F., below the closing or iopening of the switch (not shown) within the switch unit 36. The arcuate slots |09 and I0 are so arranged that the abutments |05 and ||3 which extend respectively therethrough engage the end portions thereof to limit relative movement of the annular members 8| and 84, and 83 and 92 respectively, to allow a minimum differential setting requiring about 18 F. temperature change to actuate the respective switch units 28 and 36. The slots U19-and I|0 also act to limit the maximum differential setting to about F. In this manner, when the switch unit 28 is used as a blower switch and the switch unit 36 is used as a limit switch in a blower limit combination for a heating unit such as a furnace, there is no possibility that an inexperienced operator may adjust the limit switch to open and thereby close down the heating unit prior to energization of the fan or blower which circulates the heated medium to the space to be heated. Also in like manner, there is no possibility that the blower switch will deenergize the fan or blower prior to reclosing of the limit switch unit 36 subsequent to opening thereof due to an undesired high temperature having been reached in the' heating unit.

vThe annular members 8|, 84, 89 and 92 areheld in set position subsequent to manual adjustment by the frictional force exerted therebetween and by the annular members 19, 81 and 95. As the members 19, 81 and 95 are held against rotation relative to the cylindrical member 14 and member 14 is held rigid with the shaft I8, the mem'- bers 8|, 84, 89 and 92 will be rotated in accordance with the shaft I8 except when manually moved for adjustment.

It may now be seen that this invention provides a new and useful interrelation of controlling means and actuating means therefore which is simple of manufacture, simple of operation and easily repaired in the event one of the parts becomes defective. This invention also provides a new and useful means for Calibrating a temperature actuated switch without altering the path by which the force for actuating the switch is transferred thereto from the temperature actuated means.

Whatis claimed and is desired to be secured by Letters Patent of the United States is:

1. In-an apparatus of the character described, a rockable lever having opposed cams, each cam having a cam surface, an oscillatable operating means having abutment means engageable on one stroke with `one of said cam surfaces to rock said lever-in one direction and engageable on the other stroke with the other of said cam surfaces to rock said lever in the opposite direction, a bowed leaf spring movable through center, a lever arm projecting from a face of said spring and operatively connected to said lever, said spring being operable on movement through center by said lever to complete each rocking stroke of said lever, and control means operable by said spring upon its movement through center.

2. In an apparatus of the character described, a rockable lever having opposed cams, each cam having a cam surface and a holding surface, an osclllatable operating means having abutment means engageable on one stroke with one of said cam surfaces to rock said lever in one direction and engageable on the other stroke with the other of said cam surfaces to rock said lever in the opposite direction, reacting means operable by said lever and acting during movement of vsaid lever to complete each rocking stroke of said lever, and control means operable by said reacting means, said lever alternately positioning its holding surfaces substantially parallel to the path of movement of and for lateral engagement with said abutment means.

3. In an apparatus of the character described, a rockable lever having opposed cams, each cam having a cam surface, an oscillatable operating means having an abutment member engageable on one stroke with one of said cam surfaces to rock said lever in one direction, said operating means having a second abutment member engageable on the other stroke with the other of said-cam surfaces to rock said lever in the opposite direction, reacting means operable by said lever and acting during movement of said lever to complete each rocking stroke of said lever, control means operable by said reacting means, and means to adjust the distance between said abutment members to determine the differential of operation of said control means.

4. A control device comprising a supporting member, a rotatable shaft carried by said member, a housing having a base and a cover and secured to said supporting member, control means mounted in said housing on said base, an operating arm projecting from said control means and through said cover, a rockable lever journaled exteriorly on said cover and having an aperture receiving said operating arm, spaced arms projecting from said lever and each having a cam surface, said surfaces being in opposed facingrelation. an abutment member on said shaft and engageable withone of said cam surfaces to rock said lever in one direction upon rotation of said shaft in one direction, and a second abutment member on said shaft and engageable upon rotation of said shaft in the opposite direction with the other of said cam surfaces to rock said lever in the opposite direction.

5. In an apparatus of the character described, a supporting member, a rotatable shaft carried by said member, a controlling means carried by said member and having an actuating portion, an

actuating member pivotally secured to said supporting member and operatively connected to said actuating portion, said actuating member being operable upon pivotal movement to move said controlling means, a pair of plate-like members frictionally held to said shaft and having abutting surface portions, one of said plate-like members having an arcuate aperture' therethrough concentric with said shaft, the other of said plate-like members having a protruding abutment extending through said arcuate aperture and beyond the surface of said one platelike member opposite to its abutting surface portion, a protruding abutment carried by said one plate-like member and extending from said one plate-like member opposite surface, the wall of said arcuate aperture cooperating with said sec ond-named protruding abutment to limit relative movement of said plate-like members, said, protruding abutments being operable upon rotation of said shaft to engage said actuating mem-' ber thereto to rotate said actuating member and move said controlling means.

6. In an apparatus of the character described,

a supporting member, a rotatable shaft journaled @in said member, a pin member carried by said supporting member and having its longitudinal axis substantially parallel to said shaft, a cam member pivotally carried by said pin member and having a pair of cam surfaces, a irst plate member carried by said shaft and frictionally held thereto for rotationtherewith, a first peg carried byA said plate member and engageable with one Iof said cam surfaces to move said cam member toward one position upon rotation of said shaft in one direction, a second plate member carried by said shaft and frictlonally held thereto for rotation therewith, a second peg carried by said second plate member and engageable with the other of said cam surfaces to move said cam 'member toward a second position upon rotation of said shaft in a second direction, said one surface having a surface portion spaced radially from said shaft upon movement of said cam member to said one position so that upon continued movement of said shaft in said one direction said first peg will maintain said cam member in said one position, said other surface having a surface portion spaced radially from said shaft upon movement of said cam member to said second position so that upon continued movement of said shaft in said second direction said second peg will maintain said cam member in said second position, and means actuated upon movement of said cam member. y

7. In an apparatus of the character described, a supporting member, a rotatable shaft carried by said member, a controlling means carried by said member and having an actuating portion, a U-shaped lever member having laterally spaced arms and having an aperture therein for receiving said actuating portion, said lever member being operable upon pivotal movement to actuate said controlling means, said arms having cam surfaces on their inwardly facing edge portions, a pair of plate members frictionally held to said shaft and having abutting surface portions, one of said plate members having an aperture therethrough, a protruding abutment on the other of said plate members and extending through said aperture and beyond said one plate member, a protruding abutment carried by said one plate member and extending away from said other plate member, the wall of said aperturecooperating with said first-named abutment to limit relative movement of said plate members, said protruding abutments being operable upon oscillation of said shaft to engage alternately said cam surfaces thereby to rotate said lever member and move said controlling means.

8. In a device of the character described, an adjustable operating means comprising a cylindrical member, a radially extending outwardly projecting iiange on said member and adjacent one end portion thereof, said cylindrical member having a longitudinal recess extending along an external surface thereof, a helical coil spring concentric with said cylindrical member and having one end portion abutting said iiange, a first annular member having a portion extending into said recess and held thereby for rotation with said cylindrical member, a pair of platelike members having a central aperture therethrough for receiving sald cylindrical member and rotatable relative to said cylindrical member and positioned against rst annular member, `a second annular member having a portion extending into said recess and held thereby for rotation with said cylindrical member and positioned against said pair of members, and means limiting said second annular member against movement toward the other end portion of said cylindrical member, said spring acting to urge said annular members and said plate-like members into tight frictional engagement.

9. In a device of the character described, an adjustable operating means comprising a cylindrical member, a radially extending outwardly projecting iiange on said member and adjacent one end portion thereof, said cylindrical member having a longitudinal recess extending along an external surface thereof, a helical coil spring concentric with said cylindrical member and having one end portion abutting said iiange, a rst annular member having a portion extending into said recess and held thereby for rotation with said cylindrical member, a pair of plate-like members having a central aperture therethrough for receiving said cylindrical member and rotatable relative to said cylindrical member and positioned against said rst annular member, a second annular member having a portion extend- 'ing into said recess and held thereby for rotation with said cylindrical member and positioned against said pair of members, a second pair of plate-like members having a central aperture therethrough for receiving said cylindrical memi ber and rotatable relative to said cylindrical member and positioned against said second annular member, a third annular member having a portion extending into said recess and held thereby for rotation with said cylindrical member and positioned against said second pair of members, means carried by one of said pair of members and engageable with the other of said pair of members for limiting relative rotation therebetween, and means limiting said third annular member against movement toward the other end portion of said cylindrical member, said spring acting to urge said annular members and said plate-like members into tight frictional engagement.

10. In an apparatus of the character described, a cylindrical member having a recess in its side wall and having an outwardly extending radial flange adjacent one end portion, a helical coil spring concentric with said cylindrical member and having one end portion abutting said flange, a iirst annular member positioned on said cylindrical member and having a portion tting into said recess and held thereby for rotation with said cylindrical member, a pair of plate-like members each having a central aperture therethrough and each having a segment extending from a peripheral portion thereof, said pair of members being positioned against said rst annular member with said cylindrical member extending through said central aperture, a second annular member positioned on said cylindrical member and having a portion tting into said recess and held thereby for rotation with said cylindrical member, a disk member secured to the end portion of said cylindrical member opposite to said one end portion and having a radius substantially equal to the radius of said segment-like portions, said disk member acting to limit movement of said pair of members and said annular members by said spring so that said first and said second annular members will be tightly held in engagement with said pair of members, grip members secured to said segment-like portions and extending therefrom beyond said disk member for manual movement of said pair of members relative to said cylindrical member.

ll. In an apparatus of the character described, a cylindrical member having a recess in its side lwall and having an outwardly extending radial iiange adjacent one end portion, a helical coil spring concentric with said cylindrical member and having one end portion abutting said flange, a rst annular member positioned on said cylindrical member and having a portion iitting into said recess and heldlthereby for rotation with said cylindrical member, a pair of plate-like members each having a central aperture therethrough and each having a segment-like portion extending from a peripheral portion thereof, said pair 'of members being positioned against said first annular member with said cylindrical member extending through said central aperture, a second annular member positioned on said cylindrical member and having a portion fitting into said recess and held thereby for rotation with said cylindrical member, a disk member secured to the end portion of said cylindrical member opposite to said one end portion and having a radius substantially equal to the radius of said segment-like portions, said disk member acting to limit movement of said pair of members and said annular members by said spring so that said first and said second annular members will be tightly held in engagement with said pair of members, grip members secured to said segmentlike portions and extending therefrom beyond said disk member for manual movement of said pair of members relative to said cylindrical member, a calibrated plate-like member adjustably secured to said disk member on the surface thereof away from said pair of members, and pointers carriedby said grip members and cooperable with said calibrated member to indicate the setting of said pair of members relative to said cylindrical member.

l2. In an apparatus of the character described,

a cylindrical member having a recess in its side wall and having an' outwardly extending radial ange adjacent one end portion, a helical coil spring concentric with said cylindrical member and having one end portion abutting said flange, a iirst annular member positioned on said cylindrical member and having a portion fitting into said recess and held thereby for rotation with said cylindrical member, a pair of plate-like members each having a central aperture therethrough and each having a segment-like portion extending from a peripheral portion thereof, said pair of members being positioned against said rst annular member with said cylindrical. member extending through said central aperture, a second annular member positioned on said cylindrical member and having a portion fitting into said recess and held thereby for rotation with said cylindrical member, a disk member securedl to the end portion of said cylindrical member opposite to one end portion and having a radius substantially equal to the radius of said segmentlike portions, said disk member acting to limit movement of said pair of members' and said annular members by said spring so that said rst and said second annular members will be tightly held in engagement with said pair of members, one of said segment-like portions having a slot therethrough, a pin carried by the other of said segment-like portionsand projecting through said slot, a second pin carried, by said one segmentlike portion, and means actuated by said pin members upon rotation ofA said cylindrical member.

a casing having a rear wall and spaced parallel side walls extending substantially perpendicular to said rear wall and extending from the front surface thereof, said rear wall having an aperture therethrough, a rotatable shaft extending through said aperture and into said casing, a plate spacer member having its oppositefedge portions secured tosaid side walls and extending substantially parallel to and spaced from the inner surface of said rear wall, a bearing member carried by said spacer member and extending away from said rear wall, said shaft being journaled in said bearing member, a pair of clamping rails positioned one adjacent each side wall and carried by said spaced member on the front surface thereof away from said rear wall, said spacer member having a downturned ear extending toward said rear wall and positioned adjacent one end portion, a switch housing having a pair of brated disk member to indicate the position of said shaft, a'switch member mounted on said spacer member intermediate said spacer member and said first disk member, means for actuating said switch member, and means frictionally held to said shaft and cooperable with said actuating means for actuation of said switch member upon 13. In an apparatus of the character described,

extending flanges and having a switch actuating portion, said anges being received and guided by said pair of rails, means carried by said ear for removably holding said housing against said bearing member, and means carried by said shaft and overlying said switch housing for actuation of said switch portion upon movement of said I shaft.

14. In an apparatus of the character described, a U-shaped casing having a rear wall and a pair of substantially parallel spaced side walls extending from the front surface of said rear wall, a plate-like spacer member extending between said side walls and positioned adjacent to said rear wall, a reinforcing member extending between said parallel side walls and having its front surface adjacent the front edge portions of said parallel side walls, a bearing member carried by said spacer member and having its longitudinal axis substantially parallel to said parallel side walls, said rear wall having an aperture therethrough, a shaft journaled in said bearing member and having a rearwardly extending portion extending through said aperture and a forwardly extending portion, a first disk member rigidly secured to said shaft and positioned adjacent but spaced from the rear surface of said reinforcing member, a calibrated disk member positioned against said first disk member interm'ediate said rst disk member and said reinforcing member, a pointer carried by said rein- .forcing member and cooperable with said calirotation movement of saidshaft.

l5. In an apparatus of the character described, a U-shaped casing having a rear Wall and a pair of substantially parallel spaced side walls extending from the front surface of said rear Wall, a plate-like spacer member extending between said side walls andpositioned adjacent to and spaced from said rear wall, a reinforcing member extending between said parallel side walls and having its front surface adjacent the front edge portions of said parallel side walls, a bearing member carried by said spacer member and having its longitudinal axis substantially parallel to said parallel side walls, said rear wall having an aperture therethrough aligned with said bearing member, a shaft journaled in said bearing member and having a rearwardly extending portion extending through said aperture and a forwardly extending portion, a first disk member rigidly secured on said forwardly extending shaft portion and positioned adjacent the rear surface of said reinforcing member, a calibrated disk member positioned against said rst disk member intermediate said first disk member and said reinforcing member, a pointer carried by said reinforcing member and -cooperable with said calibrated disk member to indicate the position of said shaft, a switch member carried by said spacer member intermediate said spacer member and said first disk member, means for actuating said switch member, means rotatably adjustable on said shaft and cooperable with said actuating means to actuate said switch member upon rotational movement of said shaft,

means on said adjustable means and cooperable with said calibrated disk member for indicating the position of said shaft for actuating said actuating means, a finger portion carried by said reinforcing member and positioned adjacent the peripheral portion of said calibrated disk member, and means carried by said calibrated disk member and engageable with said finger portion for limiting movement of said shaft.

16. In an apparatus of the character described, a U-shaped casing having a rear wall and a pair of substantially parallel spaced side Walls/extending from the front surface of said rear wall, a reinforcing member extending between said parallel side walls, said rear wall having an aperture therethrough, a bearing member aligned with said aperture and supported by said casing, a, shaft extending through said aperture and journaled in said bearing member, a first disk member rigidly secured to said shaft and positioned adjacent but spaced from the rear surface of said reinforcing member, a calibrated disk member adjustably secured to the front face of said first disk member, a pointer on said reinforcing member and cooperable with said calibrated disk member' to indicate the position of said shaft, a switch member positioned between said rear wall and said first disk member and having an actuating portion, operating means adjustably mounted on said shaft, means for transmitting movement from said operating means to said switch actuating portion for actuation of said switch member upon rotational movement of said shaft, indicating means on said operating means and cooperable with said calibrated disk for indicating the position of said shaft at which said operating means will actuate said actuating portion, a U-shaped cover member fitting said side and rear walls, and means carried by said reinforcing member for securing said cover member to said casing, said cover member having an aperture therethrough registering with said pointer for observation of said indicating means and of the pointer indicated position of said shaft from the exterior of said cover member.

17. In a device of the character described, a supporting member, a rotatable shaft carried by ,:aid member, a first snap acting switch carried by said member and having an actuating portion, a second snap acting switch carried by said member on the opposite side of said shaft from said first switch and having an actuating portion, a first supporting post positioned adjacent said first switch and extending substantially parallel to said shaft, a second supporting post positioned adjacent said second switch and extending substantially parallel to said shaft, a first lever member pivoted on said first post and operatively connected to and for actuating said first switch portion upon pivotal movement of said first lever member, a second lever member pivoted on said second post and operatively connected to and for actuating said second switchportion upon pivotal movement of said second lever member, a first pair of plate-like members each having an annular portion for receiving said shaft and each having a sector portion extending from one edge thereof, said sector portions being positioned in overlying relationship, one of said sector portions having an arcuate slot therethrough concentric with said shaft, the other of said sector portions having a first projecting 'pin extending through said arcuate slot and beyond said one sector portion, a second projecting pin extending from said one sector portion and away from said other sector portion, said pins, being operable to engage alternately said first lever member upon oscillation of said shaft thereby to rotate said first lever member, ya second pair of plate-like members each having an annular portion for receiving said shaft and each having a sector portion extending from one edge thereof, the second pair of sector portions being positioned in overlying closelgv, adjacentrelationship, one of said second pair of sector portions having an arcuate slot therethrough concentric with said shaft, the other of said second pair of sector portions having a first projecting pin extending through said second-named arcuate slot and beyond said one of said second sector portions, a second projecting pin carried by the other of said second pair of sector portions and extending away from said one of said second sector portions, said thirdnamed and said fourth-named pins being operable to engage alternately said second lever member upon oscillation of said shaft thereby to rotate said second lever member, means frictionally holding said first pair and said second pair of plate-like members for rotation with said shaft, means carried by each of said plate-like members for independent movement thereof relative to said shaft, and means carried by one of said pairs of members and engageable with the other of said pairs of members to limit relative movement therebetween thereby to maintain the relative operation of said switches between predetermined limits.

18. A switch mechanism comprising a casing, a pair of spaced abutments, a leaf spring having a free length greater than the distance between said abutments and being held in either of two bowed positions therebetween, a flexible blade extending substantially perpendicularly to said spring and operatively connected thereto, switch means operable by said blade. a bell crank lever having one arm securedito said spring adjacent one end portion thereof and operable to movesaid spring to either of said bowed positions, a fulcrum pin carried by'said casing, a lever member fulcrumed'on said pin and having an aperture receiving the other arm of said lever, said lever member being operable upon rotation thereof about said fulcrum to move said lever thereby to move said spring from one to another of said bowed positions, and means rigid with said casing and operable to limit rotation of said lever member.

19. In a switch mechanism, a supporting member, a switch, a shaft carried by said supporting member, force transmitting means adjustable on said shaft and operable to transmit a force lfor actuation of said switch, indicating means carried by said force means, a pointer fixed relative to said supporting member, said indicating means having a predetermined position relative to said pointer at the position of operation of said switch bv said force means, an indicia carrying means independent of the transmission of force by said force means from said shaft to said switch, the indicia of said carrying means being cooperable with said indicating means and said pointer, said carrying means being adjustable relative to said indicating means and said pointer `to calibrate the indicated operation of said switch by said shaft. y

20. A switch mechanism comprising a casing having base and cover members, a U-shaped supporting member secured to said base member and having arms extending parallel to the base of said base member, said arms each having on its inner face a longitudinal bearing groove, a leaf spring having its ends seating in said grooves and held in bowed position between said arms, switch means in said casing and operable by said spring, said base and cover members having opposed abutments adjacent said arms and operable to hold said spring against bowing movement out of said grooves, and means extending into said casing for moving said spring through center into oppositely bowed positions.

21. A switch mechanism comprising a casing'A having base and cover members, a pair of spaced abutments in said casing and secured to said base member, a leaf spring held in bowed position between said abutments, switch means operable by said spring and secured in said casing to said base member, said cover member having a plurality of apertures therethrough, a lever secured to said spring and operable to move said spring through center into oppositely bowed positions, said lever extending through one of said apertures, a bearing pin secured to said base member and extending through another of said apertures, and a lever member journaled on said pin external of said casing and operable to move said lever to actuate said switch means.

22. A switch mechanism comprising a casing, a pair of spaced abutments, a leaf spring having a free length greater than the distance between said abutments and being held in either of two bowed positions therebetween, a flexible blade extending substantially perpendicularly to said spring and operatively connected thereto, switch means operable by said blade, a bell crank lever having one arm secured to said spring adjacent one end portion thereof and operable to move said spring to either of said bowed positions, a fulcrum pin carried by said casing, a lever member fulcrumed on said pin and having operative connection with the other arm of said lever, and means to oscillate said lever member to actu/ate said switch means.

23,. In an apparatus of the character described, a control means, a lever having a fulcrum and having a pair of opposed spaced cams positioned one on each side of said fulcrum, a rotatable operating member having a pair of abutment members engageable with said cams and spaced apart a distance less than the distance between said cams, one of said abutment members being engageable with one of said cams upon rotation of said operating member in one direction to initiate movement of said lever in one direction, the other of said abutment members being engageable with the other of said cams upon rotation of said operating member in thev opposite direction to initiate movement of said lever in the opposite direction, spring means movable through center and operatively connected to said control means, a lever arm projecting from said spring means and oscillatable by said lever to position said spring means on the opposite sides of its center, said spring means being operable by reaction upon movement through center to complete each initiated movement of said lever.

24. In a switch mechanism, a supporting member having an aperture therethrough, a bearing member extending from said supporting member and secured in said aperture, a shaft journaled in said bearing member, a pair of spaced clamping rails projecting from said supporting member, switch supporting means having opposite securing portions slidable into clamped relation between said rails and said supporting member', switch mechanism carried by said switch supporting means, means on said shaft for actuating said switch mechanism, and a clamping member having a flange locking said switch supporting means against movement out of said clamped relation.

25. In a switch mechanism, a supporting member having an aperture therethrough, a bearing member extending from said supporting member and secured in said aperture, a shaft journaied in said bearing member, a pair of spaced clamping rails projecting from said supporting member, switch supporting means having opposite securing portions slidable into clamped relation between said rails and said supporting member,l said switch supporting means having an edge recess to receive a side portion of said bearing member, switch mechanism carried by said switch supporting means, means on said shaft for actuating said switch mechanism, and a screw member threaded into said supporting member and having a head engaging the edge of said supporting means opposite to said edge recess to hold said supporting means against said bearing member.

26. In a switch mechanism, a. supporting member, a switch, a shaft carried by said supporting member, an operating member frictionally held to said shaft for adjustment thereabout and operable to actuate said switch, a plate member rigid with said shaft, an indicia plate having indicia and journaled on said shaft, means for clamping said plate in adjusted position to said plate member, an indicator on said operating member and cooperable with said indicia, and an indicator rigid with said supporting member and cooperable with said indicia, said indicia plate being adjustable relative to said indicators to calibrate the indicated operation of said switch by said shaft.

27. In a switch mechanism, a supporting member, a switch, a shaft carried by said supporting member, an operating member frictionally held to said shaft for adjustment thereabout and operable to actuate said switch, a plate member rigid with said shaft, an indicia plate having indicia and journaled on said shaft, means for clamping said plate in adjusted position to said plate member, an indicator on said operating member and cooperable with said indicia, an indicator rigid with said lsupporting member and cooperable with said indicia, said indicia plate being adjustable relative to said indicators to calibrate the indicated operation of said switch by said shaft, a stop plate journaled on said shaft and cooperable with said operating member to limit adjustment of said operating member, and means to hold said stop plate in adjusted position. if;

EARNEST J. DILLMAN. i

CERTIFICATE oF CORRECTION. Patent No. 2,505,028. November 2li, l9lp2.

EARNEST J. DILIMAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows; Page 2, second column, line 57, for "member 62" read --member 61"; page 6, second column, line 22, claim 5, for "thereto" read there`oy; page 8, second column, line 8, claim lb., for rotation read --rotational--g and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

signed and sealed this 25rd day of February, A. D'. 19'45.

Henry Van Ar'sdale, (Seal) Acting Commissioner of Patents CERTIFICATE oF CORRECTION. Patent No. 2,505,028. November 2li, 191m.

EARNEST J. DILLMAN.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 5?, for memer 62" read --member 61"; page 6, second column, line 22, claim 5, for "thereto" read --ther'eby; page 8, second column, line 8, claim lb., for "rotationf read --rotational; and that the seid Letters Patent should be read with this correction therein that the same may conform to the vrecord of the case in the Patent Office.

Signedv andv sealed this 25rd day of February, A. 19'45.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents 

